Spray nozzles are utilized in many areas where a spray of fluid is required, for example: tank and drum washing; metal washing; foam control; asphalt spraying; vehicle washing; and dish washing. For tank and drum washing, one of the more popular forms of spray nozzles is the self-excited or self-driven rotating spray nozzle assembly. Such a nozzle assembly is secured to an end of a supply pipe and the device is inserted into the vessel to be cleaned either by means of entryways specifically designed for the purpose of cleaning the vessel, or by utilizing existing vessel entryways. The nozzle assembly comprises a fixed or stationary mounting element for mounting to the supply pipe, and a rotating nozzle body. A bore extends through the stationary mounting element to outlets which feed the rotating nozzle body rotatably mounted on an outlet end of the mounting element. Rotating spray nozzle assemblies generally have spray outlets which are provided in pairs opposite one another and at an angle to the axis of rotation. This provides driving forces to rotate the nozzle. The rotation is intended to distribute the spray over a specific area within the vessel to be cleaned. This area may include a portion of, or the complete interior of the vessel to be cleaned.
Inherent in the design of most nozzle units of this sort is the inability to achieve direct spray impact on either, or both, of the areas within the vessel directly in line with the axis of rotation of the rotating nozzle unit.
For many uses, the areas on the axis of the rotation of the nozzle are often the most critical areas needing spraying. Thus, spray nozzles are often used to clean a variety of containers, both for industrial uses and in the food and beverage industry. In all cases, it is exceedingly important that a vessel be fully and completely cleaned. In the case of food or beverage containers, often a residual part of the original contents will be left at the bottom, which will dry, and present problems in washing or cleaning. The base of the container is usually on the axis of a rotating spray nozzle. At the other end of the container, due to exposure to the atmosphere, portions of the contents can become encrusted around the neck or opening of the container, which is also on the axis of the spray nozzle.
To ensure proper cleaning of these areas, it is necessary that they be subjected to a vigorous spraying action.